We didn't drop those bombs for revenge. We dropped them to try and avoid a bloody landing of our troops on Japanese soil. Casualties would have been in the millions for both sides. It was a cruel thing to do but we had no choice and it did bring Japan to surrender and end the bloodshed. We had already gotten any revenge for Pearl Harbor during the course of the war. Japan would not have surrendered if it wasn't for those bombs and the Emperor finally said enough!